Pilot Trial of Botulinum Toxin and Occupational Therapy for Writer's Cramp

A visual analogue scale was used to rate patient's subjective rating of the severity of their writer's cramp at each visit. Patients were asked to mark the location on a 10 centimeter line corresponding to the severity of their writer's cramp. Ratings ranged from "mild" disease severity to "severe" disease severity. The mark was measured on the 10 centimeter line, ranging from 0 to 10. The percent change in the patient rated subject scale was measured at baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

The Writers Cramp Rating Scale (WCRS) is a tool used to quantify the treatment effect of local botulinum toxin injections in writer's cramp using writing performance and a computer assisted analysis of writing speed. The WCRS consists of two parts. Part A provides a writing movement score measuring 1) dystonic posture elbow score (ES: 0-2), 2) wrist score (WRS: 0-4), 3) finger score (FS: 0-6), 4) latency of dystonia (L: 1-2) and 5) writing tremor (WT: 0-2). The writing movement sub-score is calculated as (ES + WRS + FS) x L + (WT x 2) (0-28). Part B provides an assessment of writing speed (WS: 0-2). The WCRS score is the total of the writing movement sub-score and the writing speed sub-score. The total WCRS range is between "0" indicating absent residual writer's cramp symptoms to "30" indicating severe writer's cramp symptoms. The percentage change in the WCRS was measured at baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

The Writer's Cramp Impairment Scale (WCIS) scale assesses the speed of writing, the number of breaks during writing, the occurrence and intensity of involuntary (pathological) postures/abnormal movements (while writing, while performing repetitive wrist movements), the degree of tremor that occurs while performing repetitive spiral movements, and the presence of mirror movements. The scale ranges from 0-180 with 0 representing "no impairment" and 180 representing "severe impairment". The percent change in the WCIS was measured at baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

The Writer's Cramp Disability Scale (WCDS) is a self-reported questionnaire which queries patients regarding problems they experience with writing and other every day activities due to writer's cramp. The scale ranges from 0-42 with 0 representing "no difficulty" and 42 representing "marked difficulty". The percent change in the WCDS was measured at baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

Hand grip strength was measured using a commercially available dynamometer. The dynamometer instrument measures maximum isometric strength of the hand and forearm muscles. Hand grip strength was measured with the dynamometer during each visit. The percent change in hand grip strength between baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

Subjects with writer's cramp were instructed to draw with their dominant hand between the lines of a 5-loop Archimedes spiral presented on a paper placed over the surface of a digitizing tablet sampling pen tip position at a 100 Hz. The deviation of the drawn spiral to the ideal spiral was calculated at each sampled point. The root mean square of the total spiral error was used as a measure of dysfunctional pen control in subjects with writer's cramp compared with normative data. The percent change of the root mean square was calculated at baseline (Visit 1) and 20 weeks (Visit 8) in the two groups.

A visual analogue scale was used to rate patient's subjective rating of the severity of their writer's cramp at each visit. Patients were asked to mark the location on a 10 centimeter line corresponding to the severity of their writer's cramp. Ratings ranged from "mild" disease severity to "severe" disease severity. The mark was measured on the 10 centimeter line, ranging from 0 to 10. The percent change in the patient rated subject scale was measured at baseline (Visit 1) and 24 weeks (Visit 9) in the two groups.